Crawler shoe



- Nov. 11, 1969 e. .1. THOMPSO-N CRAWLER SHOE 5 Sheets-Sheet 1 FiledOct. 25, '19s? G. J. THOMPSON v CRAWLER SHOE Nov. 11, 1969 3Sheets-Sheet 3 Filed Oct. 25, 1967 INVENTOR GEORGE 3'. THOMPSON BYmSovgwwww %aw-1meg ATTORNEYS United States Patent ABSTRACT on THEDISCLOSURE A laminated crawler shoe composed of a plurality oftransversely extending segments, some of which carry apertured link pinlugs and others driving lugs. Wing members are located at each end ofthe assembly and threaded tension rods extend through mounting openingsin the back walls of the wing members and opening in the segments. Nuts,tightened on the threaded rods while the assembled segments are heldunder compression and the rods are held under tension, and bearing uponthe back walls of the wing members tie the assembly together. I

BACKGROUND OF THE INVENTION This invention relates to endless trackcrawlers, and more particularly to improved shoes for use in crawlertracks.

Crawler tracks are composed of a number of crawler shoes, pivotallyinterconnected to travel along an orbital path about spaced, tootheddrive wheels. Along the lower flight between drive wheels, the weight ofthe crawler and the structure it carries is imposed upon the shoesthrough rollers mounted on the frame. The shoes have been formed asmonolithic castings, cored to permit quenching and to lighten theirweight.

Crawler mounted machines have become larger and heavier with aconsequent requirement for larger crawler shoes. During the past fewyears, the size requirements for shoes have increased, to the point thatcasting has become an impractical manner of construction. For example,shoes are now in demand of ten feet, or greater, length, and the weightof each shoe is in the order of a number of tons. Consequently,procurement of the shoes has become a problem, and field damage, such asa broken pin lug, or shoe driving lug, means an extensive repair beforethe shoe can be put back into operation. The increased size also bringsproblems of materialqualities in different areas. If ductility isdesirable, then ductility is obtained even in those areas where it isnot wanted, such as at the roller path. Thus, compromise must be made ifa monolithic casting is used.

Other difiiculties, such as design compromise to permit ample flow ofquenching medium and shifting of internal cores, inherent in mostcasting operations, are amplified with the increased size of thecasting. Gore shifting, if observed prior to putting the shoe inservice, results in scrapped castings, or, if not observed, in possiblefield failures. 7

SUMMARY OF THE INVENTION The object of the present invention is toprovide an improved crawler shoe of laminated construction.

Another object of the invention is the provision of a laminated crawlershoe wherein the damaged section can be replaced in a short time, andfield repair of a broken part is not necessary.

A further object is to provide. a laminated crawler shoe which can becomposed of sections of different degrees of hardness to obtain acomposite unit having different material qualities in different areas.

Yet another object is to provide a crawler shoe which 3,477,769 PatentedNov. 11, 1969 can be assembled after the parts have been heat treated,thereby eliminating the need for quench medium passages and theinevitable quench cracking associated with large castings.

Still a further object of the invention is to provide a laminatedcrawler shoe having means to allow for a novel and simple assembly.

Other objects of the invention will become apparent from the followingdescription of one practical embodiment thereof, when taken inconjunction with the drawings which accompany, and form part of, thisspeci- .fication.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of twolaminated shoes made in accordance with the present invention and shownlinked together as in use;

FIGURE 2 is an exploded perspective view of one of the shoes;

FIGURE 3 is a top plan view of the shoe;

FIGURE 4 is a partial elevation and partial longitudinal section throughthe shoe, taken on the line 44 of FIGURE 3;

FIGURE 5 is an end elevation of the shoe, with adjacent, linked shoesshown in phantom lines; and

FIGURE 6 is a vertical transverse section through the center of theshoe, taken on the line 66 of FIGURE 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The crawler shoe 1 of thepresent invention is generally similar in over-all shape to aconventional cast shoe. However, it is composed of a center segment anda plurality of segments in similar rightand left-hand pairs arranged insuccession on opposite sides of the center segment to form a shoe whichis substantially symmetrical about the center segment. The assembledsegments are held in compressive abutment my means of nuts on threadedrods that pass through the segments. All of the segments except theouter wing sections, are cut to desired shape from heavy plate, and eachcarries a link pin lug. Shoes can be designed having different numbersof segments, to suit the needs of different installations. differentsize and weight of shoes, etc.

In the embodiment shown, there is a center segment 2. This segment hasparallel top and bottom edges, with a link pin lug 3 projecting to oneside and the opposite side being recessed, as at 4, to provide a workingpocket for the link pin lug of the next adjacent shoe of an endlesstrack. The lug 3 has a pin opening 5, and there are two, horizontallyaligned, mounting holes 6 in the segment adjacent the bottom. The topsurface 7 of the segment is concave transversely of the segment, andforms the central part of a roller path '8.

Next to the center segment, are segments 9 and 9a, segment 9 being tothe right and segment 9a being to the left of the center segment asshown in the drawings. These two segments are right-and left-handreplicas, and both have the peripheral shape of the center segment 2.They carry link pin lugs 10 and 10a with openings 11 and 11a, and havethe concave recesses 12 and 12a in their opposite edges. The topsurfaces 13 and 13a are oppositely curved in continuation of thecurvature of the center segment 2 to complete the roller path 8. Thesections also have pairs of mounting openings 14 and 14a similarlylocated to the mounting openings 6 of the center segment.

At the sides of the segments 9 and 9a, there are shoe driving lugsegments 1-5 and 15a. Here again, the seg ments are right and leftreplicas. Segments 15 and 15a carry link pin lugs 16 and 16a, but theselugs project in the opposite direction from the lugs 3, 10 and 10a. The

side edges opposite the link pin lugs are recessed at 17 and 17a.Projecting vertically from the top edges of segments and 15a are drivinglugs 18 and 18a for engagement with the teeth of the driving wheels ofthe crawler to advance the track about its pivotal path. The segmentshave pin openings 19 and 19a in the lugs 16 and 16a, and each has a pairof mounting openings 20 and 21, similarly arranged to the mountingopenings in the previously described segments.

Next to the driving lug segments are segments 21 and 21a. These areapproximately the same as the driving lug segments except that they donot have driving lugs. They have link pin lugs 22 and 22a, similarlypositioned to the lugs 16 and 16a of the driving lug segments, and theopposite edges are recessed at 23 and 23a. There are pin openings 24 and24a in the lugs 22 and 22a, and mounting openings 25 and 25a adjacentthe segment bottoms.

The last of the link pin lug bearing segments are segments 26 and 26amounted adjacent the segments 21 and 21a. These have their link pin lugs27 and 27a oppositely disposed to the last described segments andprojecting in the same direction as the center segment 2 and segments 9and 9a. These segments are recessed, as at 28 and 23a, and have pinopenings 29 and 29a in the lugs 27 and 27a, and mounting openings 30.

The assembly of units is completed by a wing member 31 on the right anda wing member 32 on the left. These members give the assembly itsdesired over-all length of bearing surface on the ground and providehousings for the securing means which tie the assembly together. Asthese two membres are slightly different, they will be separatelydescribed.

Wing member 31 has a vertical back wall 33, a bottom bearing plate 34,sides 35 and a top 36. The back wall is rectangular and has mountingopenings 37, similarly arranged and spaced to the mounting openings inthe several segments. The bottom plate 34 is welded at its back edgealong the bottom edge of the back wall. The sides are welded to the backwall and to the bottom plate. A center brace is welded to the topsurface of the bottom plate and the forward surface of the back wall tostiffen the assembly. The top 36 has its outer edge flush with the outeredges of the sides and bottom so that these four edges lie in a singlevertical plane and define an open mouth through which a tensioning toolcan be inserted, and bearing walls against which a portion of thetensioning tool may abut. The top terminates short of the back wall,leaving an access opening 38 to facilitate assembly as will bedescribed.

Wing member 32 has a back wall 39, bottom bearing plate 40, sides 41 anda front wall 42. The back, bottom plate and sides are welded together inthe same manner as those of the wing member 31. Wing member 32 has notop, but the front wall 42 is welded to the outer ends of the sides andbottom plate. A brace 43 is welded to the bottom plate and to the backand front walls. The back wall has mounting openings 44 similar to thosepreviously described.

All of the various units making up the crawler shoe are held inassembled relation by means of two tie rods 45, which pass through themounting openings of the various units. The rod ends are threaded andnuts 46 are threaded onto the rod ends which will be in the wing 32, andnuts 37 are to be threaded onto the rod ends which project into the wingmember 31.

y In assembling the shoe, the various units are arranged in the orderabove described, and can be assembled either directly on the tie rods45, or they may be preliminarily arranged by the use of positioning pinsthrough the mounting openings. If assembly dowels, or rods, are used,they will be Withdrawn and the rods 45 inserted through the open end ofthe wing member 31 and through the mounting openings in all the unitsuntil the leading ends of the rods project into the open area of thewing member 32. At this time, nuts 46 will be threaded on the ends ofthe rods within the wing member 32 and brought into abutment with theback wall of that member. Nuts 47 will be threaded onto the ends of therods projecting into the member 31, and can be rotated into contact withthe back wall of that member. No attempt is made at this time to draw upon the nuts to tighten the assembly. A suitable jack, such as that shownat 48 in dotted lines in FIGURE 4, has a threaded coupling 49 on the endof its piston rod 50, and this coupling is screwed onto the projectingend of one of the rods 45. The jack has an abutment plate 51 which isbrought into bearing contact with the outer end of the wing formed bythe edges of the bottom, side and top walls. The jack is then actuatedto draw in its piston rod to bring the units of the assembly intocompressive'abutment and to tension the rod 45. The force applied by thejack will be very great, in the order of three million pounds for largeshoes, and the assembly will be extremely rigid under this compressiveforce. By inserting a proper tool through the access opening 38 in thewing member 31, the nut 47 on the rod under tension can be drawn uptightly against the back wall 33. After the nut is tightened, the jackcan be released and the compressive force on the assembled units will bemaintained by the tie rod. The same procedure can be followed with thesecond tie rod to complete the assembly.

The completed shoe will be a tensioned assembly which will hold theindividual units against any possible movement relative to the assemblyas a whole. At the same time, the several segments making up theassembly can have different qualities as may be desired for theirparticular location in the assembly. For example, the center segment 2and the segments 9 and 9a may be quite hard to provide the propersurface for the roller path. At the same time, other segments and thewing members can have more ductility to better withstand the heavybending loads which are imposed. The laminated shoe can be fabricatedvery quickly without the usual long lead times associated with largecastings. If the shoe is damaged in service, such as by breaking a linkpin lug or driving shoe lug, it is a relatively simple repair job todisassemble the units and add a new segment of the requiredconfiguration. The laminated construction lends itself to manyvariations as far as shoe design is concerned. Yet all will be equallysimple to fabricate and to repair.

While one practical embodiment of the invention has been disclosed, itwill be understood that various modifications of the particularstructural arrangements shown and described may be made.

What is claimed is:

1. Crawler shoe comprising, a plurality of segments at the centerextending transversely of the shoe having link pin lugs projecting toone side of the shoe, the segments having upper surfaces concavelycurved transversely of the segments to form a continuous arcuate rollerpath, segments at each side of the first-mentioned plurality having linkpin lugs projecting to the other side of the shoe and driving lugsextending vertically above the segments, a separable wing member segmentat each end of the shoe having back walls in abutment with adjacentsegments, all of the segments and the wing member segments havingmounting openings in alignment lengthwise of the shoe, a tension rodhaving threaded ends extending through the mounting openings and havingthe threaded ends projecting into the wing member segments, and nuts onthe threaded ends of the rod and in abutment with the end Walls of thewing member segments holding the segments in compressive assembly andthe tension rod in tension.

2. Crawler shoe as claimed in claim 1 wherein, one of the wing membersegments has an open end aligned with the tension rod and a wallsurrounding the open end providing an abutment for a tool to tension thetension rod.

3. Crawler shoe as claimed in claim 1 wherein, the segments forming theroller path are of very hard material and the remainder of the segmentsand wing member segments are of more ductile material.

4. Crawler shoe as claimed in claim 1 wherein, all of the segments andwing member segments have second aligned mounting openings, and there isa second tension rod with nuts on the ends bearing against the wingmember segments back walls.

References Cited UNITED STATES PATENTS Leymer 30557 Knox 305--57Harrington 305-58 X Matheny 305-58 X Davidson 305-57 X RICHARD J.JOHNSON, Primary Examiner

